Tumor necrosis factor-alpha mediates the early pathology in Salmonella infection of the gastrointestinal tract

Salmonella infection of the intestinal tract results in damage to the gut epithelium. While it is generally believed that bacteria and/or bacterial products account for this pathology, the role of host factors has not been explored. Using a ligated intestinal loop model, we investigated whether tumor necrosis factor-alpha (TNF-alpha) could contribute to the tissue pathology associated with Salmonella infection. Intestinal segments infected with Salmonella typhimurium had high levels of fluid secretion as early as 6 h post-bacterial infection. At this time point, low levels of TNF activity were also present in the fluid obtained from infected segments. At 20 h post-infection, high levels of TNF activity were present in fluids obtained from infected intestinal segments and was characterized as TNF-alpha by neutralization experiments using rabbit antisera to TNF-alpha. TNF-alpha production was further verified by Northern blot analysis using RNA obtained from cells eluted from the infected intestinal segments. In contrast, no TNF activity was found in fluid obtained from intestinal segments challenged with cholera toxin, which induces fluid secretion with little to no inflammatory response. Double labeling by in situ hybridization and immunocytochemistry revealed that macrophages in the lamina propria were producing the TNF-alpha mRNA. To investigate what role TNF-alpha might play in Salmonella-induced inflammation, intestinal segments were injected with recombinant mouse TNF-alpha (rTNF-alpha) or mice were pretreated with antibody to TNF-alpha or a control antibody prior to Salmonella infection. The histological profile of intestinal segments injected with rTNF-alpha appeared identical to segments infected with S. typhimurium. Further, pathology was completely eliminated in infected mice pretreated with antibody to TNF-alpha. These results document the production of TNF-alpha in the intestinal tract following S. typhimurium infection and show that the early pathology induced by Salmonella infection of the gastrointestinal tract is mediated by immune mechanisms.

The effect of Dermatophagoides pteronyssinus allergens on proliferation and CD23 antigen expression of peripheral blood lymphocytes from atopic patients

The low affinity IgE receptor (Fc epsilon RII/CD23) has been proposed to be involved in the regulation of IgE synthesis. The present study was undertaken to investigate the responses to in vitro stimulation by allergen (Dermatophagoides pteronyssinus; D.p) and/or interleukin-4 (IL-4) of peripheral blood lymphocytes (PBLs) isolated from atopic and non-atopic subjects. IL-4 induced up to 5 fold increase in CD23 expression on PBLs from both atopic patients and normal controls, whereas the D.p extract increased CD23 expression on cells from 7 of 8 atopic donors and from 2 of 8 normal controls. The combination of IL-4 and allergen had an additive effect of CD23 expression. PBLs from 6 of 8 atopic patients but 1 of 8 normal controls showed significant proliferative responses to D.p extract whereas IL-4 did not induce any cell proliferation. The dose of D.p extract required for the maximal CD23 expression was 20 fold higher than that for cell proliferation. These results imply that allergen stimulation, presumably through proliferating allergen specific T cells which secrete IL-4, activates B cells from most atopic donors and a few non-atopic donors resulting in increased CD23 expression. This allergen-mediated CD23 expression may play an important role in specific IgE production.

Changes of IgM and IgG antibody levels in experimental rabbit anisakiasis as observed by ELISA and SDS-PAGE/immunoblot

Antibody changes in experimental anisakiasis were observed in 10 rabbits which were infected each with 10 Anisakis simplex larvae. The sera were collected before and on the 6th to the 95th day after the infection. Using crude saline extract of Anisakis larvae as antigen, specific IgM and IgG antibody levels were observed by ELISA and SDS-polyacrylamide gel electrophoresis/immunoblot. Levels of specific-IgM antibody were elevated from the 6th day, reached their peaks on the 11th day after the infection, and dropped thereafter. Serum levels of IgG antibody increased from the 6th day and reached their peak on the 26th day after the infection, and decreased gradually thereafter. When SDS-PAGE of the crude extract was done, at least forty-one SDS-polypeptide bands were recognized. Of them, IgM antibody reacted mainly to the bands of 168, 95, 74, 64, 51, 47 and 34 kDa while IgG antibody reacted strongly to 168, 92, 85, 64, 58, 52, 42 and 40 kDa bands. The crude extract showed negligible cross reactions with sera of other parasitic diseases and normal control.

Relationship between alternatively spliced exons and functional domains in tropomyosin

Smooth and striated muscle alpha-tropomyosins differ as a consequence of alternative splicing of exons 2 and 9 encoding amino acid residues 39-80 and 258-284, respectively [Ruiz-Opazo, N., Weinberger, J. & Nadal-Ginard, B. (1985) Nature (London) 315, 67-70]. To understand the relationship between alternatively spliced exons and functional domains in tropomyosin, recombinant unacetylated striated muscle, smooth muscle, and chimeric rat alpha-tropomyosins (+H3N-tropomyosins) expressed in and purified from Escherichia coli were analyzed. The functional differences between the isoforms can be primarily ascribed to exon 9. +H3N-Tropomyosins with the smooth muscle exon 9 bound to skeletal muscle filamentous actin with at least a 5-fold higher affinity than +H3N-tropomyosins with the striated muscle exon 9. On the other hand, in the presence of Ca2+, troponin increased the affinity of +H3N-tropomyosins with the striated muscle exon 9 at least 50-fold, whereas it had little effect on +H3N-tropomyosins with the smooth muscle exon 9. The unique striated muscle alpha-tropomyosin exon 9 seems to be specialized for Ca(2+)-insensitive interaction with troponin on the thin filament. The unique smooth muscle alpha-tropomyosin exon 2 was associated with a slightly lower actin affinity than the striated muscle exon 2. Although the regions encoded by exons 2 and 9 correspond to functional domains, they are not recognizable as independent units or structural domains in the extended coiled-coil structure of this fibrous actin binding protein.

Importance of rotavirus and adenovirus types 40 and 41 in acute gastroenteritis in Korean children

To examine the role of rotavirus (Rv) and adenovirus types 40 and 41 (Ad40/41) in Korean children with acute gastroenteritis, we evaluated 345 children with acute gastroenteritis and 90 children without acute gastroenteritis in Seoul, Korea, during a 29-month period. Stools were tested for group A Rv antigen and for Ad40/41 by using monoclonal antibody (MAb)-based assays. Rv was found in 68% of the ill children and 19% of the controls (P less than 0.001), whereas Ad40/41 was detected in 9% of the ill children and 2% of the controls (P less than 0.05). Also, 6% of the ill children and 0.01% of the controls excreted Rv and Ad40/41 simultaneously. Among the ill children, 96% of children with Rv and 94% of those with Ad40/41 were younger than 24 months. Although a peak of Rv infection was detected in early winter in both years of the study, there was no apparent seasonal trend with Ad40/41. Diarrhea with more than 10 stools per day, vomiting, or fever was most strongly associated with Rv shedding, whereas the first two manifestations were associated with coinfection of Rv and Ad40/41. To investigate the genetic and serotypic diversity of Rv strains, we tested 195 and 144 fecal Rv specimens isolated from the gastroenteritis cases, respectively, by polyacrylamide gel electrophoresis of the segmented RNA genome and by an enzyme-linked immunosorbent assay with serotype-specific MAbs. Of the 195 specimens, 154 yielded RNA patterns characteristic of group A Rv: 18% had short electrophoretic migration patterns, 81% had long patterns, and 1% had a mixture of short and long patterns. Of the 144 specimens, serotype specificity was determined in 51%: 89% were serotype 1, 10% were serotype 2, and 1% were serotype 3. Analysis of the specimens for which electropherotypes and serotypes were available indicated that a given RNA pattern corresponded to a particular serotype, except in one strain that showed short patterns but serotype 1. We suggest that Rv and Ad40/41 in stools be accepted critically as an important cause of diarrhea among young children in Korea.

Coordination complex of Na+ and alpha-D-glucose

The structure of alpha-D-glucose-NaCl is presented. C6H12O6.1/2(NaCl).0.39(H2O), Mr = 216.40, trigonal, P3(1)21, a = b = 9.721 (3), c = 17.06 (1) A, V = 1396 (1) A3, Dm = 1.54 (1), Dx = 1.54 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 2.859 cm-1, F(000) = 683.4, T = 293 K, final R = 0.044 for 744 reflections with I greater than or equal to 3 sigma (I). The Na+ residues on a crystallographic twofold axis and is coordinated by six hydroxyls originating from four separate glucose molecules. The chloride ion is not involved in direct ionic interactions with the sodium ion.

The amino terminus of muscle tropomyosin is a major determinant for function

The amino-terminal region of muscle tropomyosin is highly conserved among muscle and 284-residue non-muscle tropomyosins. Analysis of fusion and nonfusion striated alpha-tropomyosins and a mutant in which residues 1-9 have been deleted has shown that the amino terminus is crucial for function. The presence of 80 amino acids of a nonstructural influenza virus protein (NS1) on the amino terminus of tropomyosin allows magnesium-independent binding of tropomyosin to actin. The fusion tropomyosin inhibits the actomyosin S1 ATPase at all myosin S1 concentrations tested, indicating that the presence of the fusion peptide prevents myosin S1 from switching the actin filament from the inhibited to the potentiated state. Nonfusion tropomyosin, an unacetylated form, has no effect on the actomyosin S1 ATPase, though it regulates normally with troponin. Deletion of residues 1-9, which are believed to overlap with the carboxyl-terminal end of tropomyosin in the thin filament, results in loss of tropomyosin function. The mutant is unable to bind to actin, in the presence and absence of troponin, and it has no regulatory function. The removal of the first 9 residues of tropomyosin is much more deleterious than removal of the last 11 by carboxypeptidase digestion. We suggest that the structure of the amino-terminal region and acetylation of the initial methionine are crucial for tropomyosin function.

Semisynthetic hemoglobin A: reconstitution of functional tetramer from semisynthetic alpha-globin

The optimal conditions for the semisynthesis of alpha-globin through Staphylococcus aureus V8 protease condensation of a synthetic fragment (alpha 1-30) with the complementary apo fragment (alpha 31-141) in the presence of structure-inducing organic cosolvents and the reconstitution of the functional tetramer from semisynthetic alpha-globin have been investigated. The protease-catalyzed ligation of the complementary apo fragments alpha 1-30 and alpha 31-141 proceeds with very high selectivity at pH 6.0 and 4 degrees C in the presence of 1-propanol as the organic cosolvent. A 30% 1-propanol solution was optimal for the semisynthetic reaction, and the synthetic reaction attained an equilibrium (approximately 50%) in 72 h. The synthetic reaction proceeds smoothly over a wide pH range (pH 5-8). Besides, the semisynthetic system is flexible, and it also proceeded well if trifluoroethanol or 2-propanol was used instead of 1-propanol. However, glycerol, a versatile organic cosolvent used in all other proteosynthetic reactions reported in the literature, was not very efficient as an organic cosolvent in the present synthetic reaction. The semisynthetic alpha-globin prepared with 1-propanol as the organic cosolvent has been reconstituted into HbA. The semisynthetic HbA was then purified by CM-cellulose chromatography. The semisynthetic HbA is indistinguishable from native HbA, in terms of its structural and functional properties. The semisynthetic approach provides the flexibility in protein engineering studies for the incorporation of spectroscopic labels (13C- and/or 15N-labeled amino acids), noncoded amino acids, or unnatural bond functionalities, which at present is not possible with genetic approaches.

Etiology of childhood diarrhea in Korea

To assess the role of recently recognized enteropathogens in childhood diarrhea in Korea, 231 children with diarrhea admitted to and 104 children without diarrhea seen at the well-baby clinic or the outpatient department of Hanyang University Hospital in Seoul, Korea, were evaluated during a 14-month period. Stools were cultured for bacterial pathogens, including enterotoxigenic (heat-labile and heat-stable enterotoxin-producing) and enteroadherent organisms. Only those stools obtained from patients with diarrhea were examined for rotavirus. All Escherichia coli isolates were screened for Shiga-like toxin (SLT) I, SLT-II, enterohemorrhagic E. coli fimbriae, and enteroinvasiveness by colony hybridization. One or more pathogens were identified in 75.8% of the children with diarrhea. Rotavirus was the most frequently identified pathogen, accounting for 47% of the cases. Other major enteropathogens were enterotoxigenic E. coli (22%), Clostridium difficile (16%), enteroadherent E. coli (15%), and enteropathogenic E. coli (6%). Shigella spp., Campylobacter jejuni, Salmonella spp., SLT-I-and enterohemorrhagic-E. coli-fimbria-probe-positive E. coli serotype O26:H11 and enteroinvasive E. coli were isolated from only a few patients. Aeromonas hydrophila and E. coli O157 were not isolated. Compared with those of the controls, the isolation rates of heat-stable-enterotoxin-producing E. coli (P less than 0.05), C. difficile (P less than 0.025), and enteroadherent E. coli (P less than 0.05) were significantly higher in the patients with diarrhea. The greatest number of rotavirus, enterotoxigenic E. coli, and C. difficile cases were identified during the cool, dry months of October and November.

Complex of N-phosphonacetyl-L-aspartate with aspartate carbamoyltransferase. X-ray refinement, analysis of conformational changes and catalytic and allosteric mechanisms

The allosteric enzyme aspartate carbamoyltransferase of Escherichia coli consists of six regulatory chains (R) and six catalytic chains (C) in D3 symmetry. The less active T conformation, complexed to the allosteric inhibitor CTP has been refined to 2.6 A (R-factor of 0.155). We now report refinement of the more active R conformation, complexed to the bisubstrate analog N-phosphonacetyl-L-aspartate (PALA) to 2.4 A (R-factor of 0.165, root-mean-square deviations from ideal bond distances and angles of 0.013 A and 2.2 degrees, respectively). The antiparallel beta-sheet in the revised segment 8-65 of the regulatory chain of the T conformation is confirmed in the R conformation, as is also the interchange of alanine 1 with the side-chain of asparagine 2 in the catalytic chain. The crystallographic asymmetric unit containing one-third of the molecule (C2R2) includes 925 sites for water molecules, and seven side-chains in alternative conformations. The gross conformational changes of the T to R transition are confirmed, including the elongation of the molecule along its threefold axis by 12 A, the relative reorientation of the catalytic trimers C3 by 10 degrees, and the rotation of the regulatory dimers R2 about the molecular twofold axis by 15 degrees. No changes occur in secondary structure. Essentially rigid-body transformations account for the movement of the four domains of each catalytic-regulatory unit; these include the allosteric effector domain, the equatorial (aspartate) domain, and the combination of the polar (carbamyl phosphate) and zinc domain, which moves as a rigid unit. However, interfaces change, for example the interface between the zinc domain of the R chain and the equatorial domain of the C chain, is nearly absent in the T state, but becomes extensive in the R state of the enzyme; also one catalytic-regulatory interface (C1-R4) of the T state disappears in the more active R state of the enzyme. Segments 50-55, 77-86 and 231-246 of the catalytic chain and segments 51-55, 67-72 and 150-153 of the regulatory chain show conformational changes that go beyond the rigid-body movement of their corresponding domains. The localized conformational changes in the catalytic chain all derive from the interactions of the enzyme with the inhibitor PALA; these changes may be important for the catalytic mechanism. The conformation changes in segments 67-72 and 150-153 of the regulatory chain may be important for the allosteric control of substrate binding. On the basis of the conformational differences of the T and R states of the enzyme, we present a plausible scheme for catalysis that assumes the ordered binding of substrates and the ordered release o

Cross-linking of proteins by aldotriose: reaction of the carbonyl function of the keto amines generated in situ with amino groups

Nonreductive modification of proteins with glyceraldehyde forming 2-oxo-3-hydroxypropylated protein is mechanistically analogous to nonenzymic glycation reactions. The latent cross-linking potential of glyceraldehyde as a consequence of the reactivity of the carbonyl function of 2-oxo-3-hydroxypropyl groups of nonreductively modified protein has been now investigated. Reaction of RNase A (0.5 mM) with glyceraldehyde (20 mM) at pH 7.4 and 37 degrees C for 4 h resulted in the intermolecular cross-linking of the protein, with the concomitant development of a yellow chromophore with two new absorption bands having maxima around 305 and 375 nm. The product exhibited a fluorescence that had excitation and emission maxima around 365 and 450 nm, respectively. The presence of NaCNBH3 during the reaction, which selectively reduces the Schiff base adducts of aldotriose to form 2,3-dihydroxypropyl groups on proteins, inhibited both the cross-linking reaction and the development of the absorption and fluorescence characteristics. The hydroxymethyl group of the aldotriose is not an essential moiety since the cross-linking potential of glyceraldehyde is comparable to that of glyceraldehyde 3-phosphate. The formation of cross-links appears to involve the carbonyl function of the keto amines resulting in the formation of Schiff base adducts (ketimine linkages) as the initial event. Consistent with this, incubation of 2-oxo-3-hydroxypropylated RNAse A with [14C]glycine ethyl ester resulted in the incorporation of the reagent into the protein. The cross-linking reaction was inhibited when the reaction of RNase A with glyceraldehyde was carried out in the presence of amino compounds, such as glycine ethyl ester, ethanolamine, glucosamine, and aminoguanidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial invasion of fibroblasts induces interferon production

Although bacteria and/or bacterial products have been shown to induce interferon (IFN) production in cells of the immune system, the ability of non-lymphoid cells to produce IFN in response to bacterial products and/or bacterial invasion is currently unknown. In this study we examined murine and human fibroblasts for their ability to produce IFN in response to challenge with the invasive bacteria Shigella flexneri and enteroinvasive Escherichia coli. Both human and murine primary cell cultures produced high levels (500 to 1000 U/ml) of IFN-beta within 12 hr after Shigella invasion. The production of IFN appeared to be dependent upon bacterial invasion because no IFN was produced by cells pretreated with a non-invasive isogenic variant of S. flexneri. Furthermore, UV treated invasive S. flexneri, which lose the ability to invade cells, failed to induce IFN production in fibroblasts after bacterial challenge. In contrast to primary cells, most human and murine continuous cell lines did not produce IFN in response to Shigella invasion. The above results demonstrate that bacterial invasion of primary cultures of fibroblasts can induce IFN production. Taken together with previous findings, these results suggest that IFN may play an important front line host defense against invasive bacterial infections.

Bacterial invasion of fibroblasts induces interferon production

Although bacteria and/or bacterial products have been shown to induce interferon (IFN) production in cells of the immune system, the ability of non-lymphoid cells to produce IFN in response to bacterial products and/or bacterial invasion is currently unknown. In this study we examined murine and human fibroblasts for their ability to produce IFN in response to challenge with the invasive bacteria Shigella flexneri and enteroinvasive Escherichia coli. Both human and murine primary cell cultures produced high levels (500 to 1000 U/ml) of IFN-beta within 12 hr after Shigella invasion. The production of IFN appeared to be dependent upon bacterial invasion because no IFN was produced by cells pretreated with a non-invasive isogenic variant of S. flexneri. Furthermore, UV treated invasive S. flexneri, which lose the ability to invade cells, failed to induce IFN production in fibroblasts after bacterial challenge. In contrast to primary cells, most human and murine continuous cell lines did not produce IFN in response to Shigella invasion. The above results demonstrate that bacterial invasion of primary cultures of fibroblasts can induce IFN production. Taken together with previous findings, these results suggest that IFN may play an important front line host defense against invasive bacterial infections.

Dietary manipulation of the disappearance of trans-octadecenoates in rat tissues

The effects of dietary manipulations on the fate of trans-octadecenoates deposited in the tissues of rats were examined. Male rats were fed on a 15% fat diet containing trans-octadecenoic acids (46.6% of total fatty acids) for 35 days followed by various diets free of trans-fatty acids. After removal of trans-fatty acids from the diet, there were phased disappearances of trans-octadecenoates from the circulation; a rapid and broad reduction in one day and a slow and gradual reduction thereafter. The rate of the initial reduction in serum trans-octadecenoates was highest on a high fat (20%) diet in relation to low fat (1 or 5%) diets. However, the disappearance rate at the later stage was apparently the same among the various groups and trans-fatty acid contents in the serum declined to about 10% of the initial value in 2 weeks and thereafter. After 35 days, the concentration of trans-octadecenoates remaining in the adipose tissue was markedly lower in rats fed on a high protein (40%) diet. The effects of dietary fat type and cholesterol on the fate of serum trans-octadecenoates were virtually the same, but livers from rats fed on the cholesterol-free safflower oil diet contained more trans-fatty acids than those from rats fed on the corresponding olive oil diet. Thus, the amounts of trans-fatty acids stored in the tissues cannot be merely predicted from serum levels. It seems that both dietary fat and protein affect the metabolic rate of trans-octadecenoates in rats.

Natural and recombinant interferons inhibit epithelial cell invasion by Shigella spp

The effect of natural and recombinant interferons (IFNs) on the abilities of Shigella flexneri, S. sonnei, and Salmonella typhimurium to invade different human and murine cells was examined. Pretreatment of cell monolayers with natural and recombinant IFNs reduced the number of Shigella-infected cells in a dose-dependent manner. Establishment of an anti-invasive cellular state was time dependent, requiring 10 h for 50% inhibition of bacterial invasion. The inhibitory effect of IFN was species specific, with human or murine IFN effective against homologous but not heterologous cells. Gamma IFN was slightly more potent than alpha IFN at inhibiting bacterial invasion. Inhibition of Shigella invasion was dependent on the challenge dose of bacteria. Little inhibition of invasion was seen when cells were pretreated with low concentrations of IFN and challenged with high multiplicities of infection of Shigella sp. In contrast to Shigella invasion, the maximum inhibitory effect of IFN on Salmonella invasion of cells was observed at low levels (5 to 50 U) of IFN. These results suggest that Shigella and Salmonella invasions occur at unique sites on eucaryotic cells or by different penetration mechanisms. More importantly, these data suggest that IFN may play a significant role in host defense against Shigella and Salmonella infections.

Effects of different levels of dietary trans-octadecenoate on steroid metabolism in rats

Rats were fed semipurified diets containing olive oil or partially hydrogenated corn oil at the 5 or 20% level for ca. 30 days. These fat diets contained the same amount of octadecenoate but differed in the geometry with respect to each fat level. Contents of t-18:1 were 26% and 41% of total fatty acids, respectively. The linoleic acid content was also made equivalent (3.8 energy %). After feeding on cholesterol-free diets, rats on trans fat, compared to those on cis fat, showed: (a) no changes in serum cholesterol and apolipoprotein levels, (b) no effects on the bile flow and concentrations of biliary cholesterol or bile acids, (c) a trend toward increased fecal excretion of neutral and acidic steroids, (d) a lesser extent of transformation of cholesterol to coprostanol in the gut, and (e) no changes in the composition of biliary and fecal bile acids. Observations (c) and (d) were more marked with a high trans fat regimen. These observations, except for serum apolipoproteins and fecal steroid excretion, were practically reproducible even when rats were fed cholesterol-enriched diets.

Conversion of Elymoclavine to Paspalic Acid by a Particulate Fraction from an Ergotamine-Producing Strain of Claviceps sp

The particulate fraction from the ergotamine-producing strain CLAVICEPS sp. PCCE1 catalyzed the conversion of [ (14)C]elymoclavine to paspalic acid. NADPH was required. Maximum conversion was 95%. Carbon monoxide (CO:0 (2), 4:1) and SK&F 525A (1.0 mM), cytochrome P-450 inhibitors, inhibited the conversion 94% and 50%, respectively. Minor amounts of paspalic acid (0.1 mg/1) were present in cultures. The particulate fraction from CLAVICEPS sp. SD 58, which accumulates elymoclavine in cultures, lacked activity for the conversion of elymoclavine to paspalic acid.

Effects of dietary trans-fat on biliary and fecal steroid excretion and serum lipoproteins in rats

Rats were fed cholesterol-free or cholesterol-enriched diets containing olive oil or partially hydrogenated corn oil at the 10% level for ca. 30 days (c-18:1, 77.0% in the former diet and c-18:1,24.7% and t-18:1,42.5% in the latter). The linoleic acid content of these fat diets was made equivalent (1.7 energy %). After feeding cholesterol-free diets, trans fat compared to cis fat showed (a) no untoward effects on growth parameters, (b) a reduction of serum cholesterol levels without influencing concentrations of serum apolipoproteins A-1, B and E, (c) no effects on the bile flow and the concentration of biliary cholesterol and bile acids, (d) an increasing trend of fecal excretion of neutral and acidic steroids, both in terms of mg/day and mg/g feces, and (e) rather equivocal change in the composition of fecal, but not biliary steroids. Similar response patterns were also observed when cholesterol-enriched diets were fed except for a decrease in serum apo B and an ineffectiveness to increase fecal acidic steroids. Together with the results obtained from experiments simultaneously performed with safflower oil and completely hydrogenated corn oil, it seems that the steroid metabolism can be specifically modified by the geometry of dietary fats.

Biliary and fecal steroid excretion in rats fed partially hydrogenated soybean oil

Male Wistar rats were fed cholesterol-free or cholesterol-enriched diets containing partially hydrogenated soybean oil with different levels of trans-fatty acids or unhydrogenated soybean oil at the 10% level. The linoleic acid content of hydrogenated fat diets was adjusted to 3.6% of the total energy. Hydrogenated fat diets contained 29% and 41% trans-acids, mainly as t-18:1. Trans-fats exerted no untoward effects on growth parameters, but increased liver weight. Dietary hydrogenated fats influenced neither the concentration nor composition of biliary steroids, irrespective of the presence or absence of cholesterol in the diet. In rats fed a cholesterol-free diet, daily fecal output of neutral and acidic steroids was enhanced by hydrogenated fats and the magnitude of augmentation was proportional to the dietary level of trans-fatty acids. The increased fecal steroid excretion corresponded to an increase in total excreta. Hydrogenated fats also tended to enhance bile acid excretion when feeding a cholesterol-enriched diet. The results suggest that dietary trans-fatty acids, in relation to cis-polyunsaturated fatty acids, provoke demonstrable change in steroid homeodynamics.

IgE antibody production to exoenzymes and common antigen (OEP) of Pseudomonas aeruginosa in mice

IgE antibody production to exoenzymes and common antigen (OEP) of P. aeruginosa was studied in mice that were injected with the antigens incorporated into water-in-oil-in-water (w/o/w) emulsion or Al(OH)3 gel. OEP and protease toxoid (PT) elicited IgE antibody response but elastase toxoid (ET) did not. Capacity of the OEP to produce IgE antibody was reduced remarkably by it's protease treatment, which suggested that the capacity lies in the protein portion of OEP. The w/o/w emulsion was less effective than Al(OH)3 gel in adjuvanticity to elicit IgE antibody response, but the emulsion enhanced the IgM and/or IgG antibody response to PT and maintained a constant level for a long period. These findings may suggest that IgE antibody response to some components of P. aeruginosa could be induced in man. High serum level of IgE was observed in some cases of cystic fibrosis caused by P. aeruginosa infection, although the IgE antibody activity has not yet been determined.

Citation characteristics of periodical literature in veterinary science

The usage of periodical literature in veterinary science was measured by means of citation analysis. Eighty-two percent of the citations in the source of this study, Advances in Veterinary Science and Comparative Medicine (1970-1974), were from periodicals, and 70 of the 743 periodical titles cited (9.4%) contributed 66% of the total periodical citations. Periodical literature cited in the source of the study appeared to have a half-life of 6.1 years, and to double its size approximately every 20 years. The aging patterns of the periodical literature seemed to vary with the publishing age of the periodical, i.e., the literature in the periodicals which have been in publication for more than 40 years showed a more gradual aging pattern than did that in the newer periodicals.